Which two components make up the empennage?

The empennage of an aircraft refers to the tail unit which is crucial for stability and control during flight. It primarily includes the rudder and stabilizers. The rudder is a vertical control surface located on the tail that helps to manage the aircraft's yaw, or side-to-side movement. Stabilizers, which can be horizontal (horizontal stabilizer) or vertical (vertical stabilizer), are pivotal in maintaining balance and control of the aircraft's pitch and yaw, respectively.

In contrast, the other options do not accurately describe the components of the empennage. Elevators and ailerons, while important control surfaces, are part of different sections of the aircraft – elevators are typically located on the horizontal stabilizer, responsible for controlling pitch, and ailerons are located on the wings, aiding in roll movement. Flaps and slats are components found on the wings that enhance lift during takeoff and landing but do not relate to the tail unit. Lastly, the nacelle and landing gear pertain to the engine housing and wheels, respectively, which are entirely separate from the empennage's purpose and functionality.